Bug Report: Jakarta Activation Framework 2.1.4 appears to have broken MIME type detection

[rdelaplante]

Brief Summary

My application works well on Payara 6.2025.9 but not on 6.2025.10. I use Jakarta Activation Framework to detect MIME types of files like this:

import jakarta.activation.MimetypesFileTypeMap;

File file = ...
String mimeType = new MimetypesFileTypeMap().getContentType(file);

It used to output correct values such as "text/css", "image/png", etc. but now outputs "application/octet-stream" for all files causing web browsers to not render my resources.

I noticed jakarta.activation-api was upgraded from 2.1.3 to 2.1.4 in the Payara 6.2025.10 release. They seem to have renamed "mailcap" to "jakarta.mailcap", though I have not investigated what that is or where it is located:

jakartaee/jaf-api@5f213b8

I think this broke Payara 6.2025.10 and I cannot upgrade to this release or future releases until this is resolved.

Expected Outcome

MimetypesFileTypeMap().getContentType(file) should return the correct MIME type instead of "application/octet-stream" for all files.

Current Outcome

MimetypesFileTypeMap().getContentType(file) returns "application/octet-stream" for all files.

Reproducer

import jakarta.activation.MimetypesFileTypeMap;

File file = ...
String mimeType = new MimetypesFileTypeMap().getContentType(file);

I'm using that in a servlet that outputs files to the browser.

Operating System

Windows 11 Pro

JDK Version

Eclipse Adoptium 17.0.15+6

Payara Distribution

Payara Server Full Profile

[rdelaplante]

This turns out to be related to the /src/main/resources/META-INF/mime.types file that I have in my Maven war project. Renaming mime.types to jakarta.mime.types fixes the problem in Payara 6.2025.10, but causes the same issue to occur in Payara 6.2025.9. To make it work in both versions of Payara, I needed to make a copy of the file so that I have both mime.types and jakarta.mime.types in /src/main/resources/META-INF/.

This breakage might warrant mention in the Payara 6.2025.10 release notes.